Organic nitrate esters such as, for example, glyceryl trinitrate, commonly referred to as "nitroglycerin," are well known antihypertensive agents. Administration of organic nitrate esters results in, for example, the relaxation of vascular smooth muscle. Patients having hypertension, angina pectoris, congestive heart disease, myocardial infarction, peripheral vascular disease and airways diseases often receive ongoing nitrate therapy.
It is well known that the magnitude and duration of the desired activities of nitrates diminish on chronic, continuous dosing of nitrates. This diminished activity is commonly referred to as "nitrate tolerance." While nitrate tolerance can often be avoided or reduced by intermittent versus chronic, continuous dosing, undesirable events, e.g., "rebound angina," may occur during such nitrate-free periods.
Accordingly, nitrate-induced tolerance diminishes the efficacy of the nitrate therapy, and increased doses of organic nitrate esters are often administered to provide the desired therapeutic and pharmacological effects. Efforts have been made to reduce or reverse nitrate-induced tolerance by determining, for example, how the effects of organic nitrate esters are mediated on a cellular level.
On a cellular level, cyclic guanosine 3',5'-monophosphate ("cGMP") is thought to be the second messenger through which the vascular and other effects of organic nitrate esters are mediated. Briefly, cGMP is formed from guanosine 5'-triphosphate by the enzyme guanosine 5'-triphosphate pyrophosphate ("guanylate cyclase"). The termination of cGMP action is catalyzed by cyclic nucleotide phosphodiesterases ("PDEs") which cause the opening of a 3',5'-cyclic phosphoester bond yielding 5'-cGMP.
Organic nitrate esters are known to activate guanylate cyclase leading to increased cGMP levels, and tolerance to nitrates is associated with a reduced ability to generate cGMP. Nitrate-induced increased cGMP levels can be maintained either through less degradation of existing cGMP or by increased synthesis of cGMP. For example, inhibitors of cGMP-specific cyclic nucleotide PDEs can be used to block the termination of cGMP action by maintaining cGMP levels, e.g., provided by organic nitrate ester activation of guanylate cyclase.
Reversal of nitroglycerin tolerance in vitro by a cGMP PDE inhibitor, i.e., zaprinast (also known as "M&B 22,948"), has been described in articles by: P. J. Silver et al. published in the European Journal of Pharmacology, Vol. 199 (1): pp. 141-142 (1991), T. L. G. Anderson et al. published in the Journal of Cardiovascular Pharmacology, Vol. 18 (2): pp. 237-242 (1991), L. A. Merkel et al. published in the European Journal of Pharmacology, Vol. 216 (1): pp. 29-35 (1992), L. De Garavilla et al. published in the Journal of Molecular and Cellular Cardiology, Vol. 24 (Suppl. 3): S37 (1992) and in the European Journal of Pharmacology, Vol. 313 (1-2): pp. 89-96 (1996), and by E. D. Pagani et al. published in the European Journal of Pharmacology, Vol. 243 (2): pp. 141-7 (1993).
Synergism of a cGMP PDE inhibitor, i.e., E4021, with nitroglycerin, has been described in an article by T. Saeki et al. published in the Journal of Pharmacology and Experimental Therapeutics, Vol. 272 (2): pp. 825-831 (1995) (an increase in cGMP levels and a relaxant effect in isolated porcine coronary artery).
Reversal of nitroglycerin tolerance in vitro by a cGMP PDE inhibitor, i.e., cicletanine, has been described in an article by Z. Szilvassy et al. published in the Journal of Molecular and Cellular Cardiology, Vol. 28 (5): A97 (1996).
U.S. Pat. No. 5,294,612 discloses 6-heterocyclyl-pyrazolo[3,4-d]pyrimidin-4-ones possessing cGMP PDE I inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. No. 5,488,055 and International PCT Application published as WO 96/28446 disclose substituted N-cycloalkylmethyl-1H-pyrazolo[3,4-b]quinolin-4-amines possessing c-GMP PDE V inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. No. 5,541,187, a division of the aforementioned U.S. Pat. No. 5,294,612, discloses 6-heterocyclyl-pyrazolo[3,4-d]pyrimidin-4-ones possessing cGMP PDE I inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. No. 5,614,530 and International PCT Application published as WO 96/128159 disclose substituted N-arylmethyl and heterocyclylmethyl-1H-pyrazolo[3,4-b]quinolin-4-amines possessing c-GMP PDE V inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. No. 5,656,629 and International PCT Application published as WO 96/28429 disclose 6-substituted pyrazolo[3,4-d]pyrimidin-4-one derivatives possessing c-GMP PDE V inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. No. 5,736,548 and International PCT Application published as WO 96/28448 disclose 6-arylpyrazolo[3,4-d]pyrimidin-4-one derivatives possessing c-GMP PDE V inhibitory activity, and the use of such compounds in combination with nitrates to reverse and/or reduce nitrate-induced tolerance.
U.S. Pat. Nos. 5,250,534, 5,272,147, and 5,346,901, a division of the aforementioned U.S. Pat. No. 5,250,534, and International PCT Applications published as WO 93/06104, WO 93/07149, WO 94/28902 and WO 98/49166, disclose pyrazolo[4,3-d]pyrimidinones possessing cGMP PDE inhibitory activity.
U.S. Pat. No. 5,734,053 and International PCT Application published as WO 94/00453 disclose purinones possessing cGMP PDE inhibitory activity.
U.S. Pat. No. 5,482,941 and International PCT Application published as WO 93/12095 disclose quinazolinones possessing cGMP PDE inhibitory activity.
U.S. Pat. No. 5,591,742 and International PCT Application published as WO 94/05661 disclose pyridopyrimidinones possessing cGMP PDE inhibitory activity.
International PCT Application published as WO 96/16657 discloses 5-arylpyrazolo[4,3-d]pyrimidin-7-ones, 6-arylpyrazolo[3,4-d]pyrimidin-4-ones, 2-arylquinazolin-4-ones, 2-arylpurin-6-ones and 2-arylpyrido[3,2-d]pyrimidin-4-ones possessing cGMP PDE inhibitory activity.
International PCT Application published as WO 95/19978 discloses tetracyclic derivatives possessing cGMP PDE inhibitory activity. International PCT application published as WO 97/03675 discloses the use of such tetracyclic derivatives to treat impotence.
The present invention relates to the use of certain pyrazolo[4,3-d]pyrimidin-7-ones, pyrazolo[3,4-d]pyrimidin-4-ones, quinazolin-4-ones, purin-6-ones, pyrido[3,2-d]pyrimidin-4-ones and tetracyclic derivatives for the treatment of nitrate-induced tolerance.
All of the documents cited herein, including the foregoing, are incorporated by reference herein in their entireties.